1. Field of the Invention
This invention relates generally to gesture input to computer systems, and more particularly to visually detecting a change in a device, wherein the change triggers an action on the part of the computer system.
2. Description of the Related Art
There has been a great deal of interest in searching for alternatives to input devices for computing systems. In particular, visual gesture input devices are becoming more popular. Generally speaking, gesture input refers to having an electronic device such as a computing system, video game console, smart appliance, etc., react to some gesture captured by a video camera that tracks an object.
Tracking of moving objects using digital video cameras and processing the video images for producing various displays has been known in the art. For example, FIG. 1 shows hand of a user holding ball 101. Ball 101 may be placed within a field of view of a video camera, and the video camera may track the position of the ball by detecting the circular shape of the ball. Once the position of ball 101 is known, it is then possible to use this information to control a computer program in any number of different ways which are generally known in the art. As an example, there can be a virtual object that forms a moving image on a monitor corresponding to how one moves around ball 101. To display the virtual object, the calculated information is used for fixing the position and orientation of the virtual object in a memory space of a computer, and then rendering of the image is performed by known processing to convert the three-dimensional information into a realistic perspective display.
However, in spite of the above knowledge and techniques, problems continue to hinder successful object tracking, and a particularly difficult problem is extracting precisely only those pixels of a video image that correspond unambiguously to ball 101 of interest. For example, as shown in FIG. 1, the hand holding ball 101 partially blocks the ball. As a result, the image of ball 101 captured by video camera is not perfectly circular in shape. Object tracking methods that rely on detecting a particular circular object are highly susceptible to error because ball 101 is partially blocked by hand holding the ball.
In another example, the video camera may additionally track a glove worn on the hand of a user, where the glove includes sensors that are tracked by a video camera to capture input. While this glove has been tried, users have not embraced the glove because of the inconvenience of having to continually remove and put on the glove.
Thus, there is a need to provide a more reliable method and system to track an interface object, wherein the interface object is convenient for the user.